Change-over device



1941- J. .1. SHANLEY 2,253,944

.CI-IIANGE-OVER DEVICE Filed Feb. 19, 1940 Fla. 2

INVENTOR JAMES J. SHANLE Patented Aug. 26, 1941 CHANGE-OVER DEVICE JamesJ. Shanley, Bartlesville, kla., assignor to Phillips Petroleum Company,a corporation of Delaware Application February 19, 1940, Serial No.319,787

4 Claims.

The present invention relates to improvements in devices forautomatically changing withdrawal connections from one source of highpressure gas to another upon decrease in pressure in the first source.

Liquefied petroleum gas, such as propane, butane, or a mixture of thetwo, is now being marketed extensively in tanks or cylinders. In makinguse of this liquefied gas for operating gas consuming appliances, suchas domestic gas ranges, it is customary to provide the customer withtwo-containers with some means of connecting them to a service linethrough a suitable arrangement of valves and pressure regulators. Theusual procedure is to use one of the cylinders as the active source ofthe gas supply, keeping the other cylinder as a reserve source until thefirst cylinder is exhausted. It is then necessary to cut ofi theexhausted source and establish connection with the reserve source.- Inprior practice, the valve on the active cylinder was opened while thevalve on the reserve cylinder was kept closed. When the gas in theactive cylinder became exhausted the valve on that cylinder was closedand the valve on the reserve cylinder opened. The disadvantage of thissystem was that the customer had to go to the place where the cylinderswere housed, usually outside, and change the valves each time one of thecon-- tainers became depleted. Sometimes, a container became depleted atnight or while the customer was not at home and the result was thatthere was a cessation in the gas supply and all pilot lights wereextinguished. Recently there have been developed various systemsequipped with socalled. automatic valves, whereby upon the pressure inthe active container becoming low, the vapor in the reserve containerwill be drawn upon but the valve must be reset for a second cycle. For'some time it has been desirable to produce a fully automatic changeoverdevice that does not have to be previously set manually before iteiiects a changeover of withdrawal connections. An important object ofthis invention is to provide an improved automatic changeover de-.

Fi ure l is a view in vertical section of a device embodying the presentinvention,

Figures 2 and 3 are enlarged fragmentary views of some of the elementsshown in Figure 1 and illustrating movements of the same.

Referring more specifically to the drawing, reference numeral 8designates a casing or body member having inlet conduits 9, l0, and anoutlet conduit Tire valve cores or any other suitable valves I2 and [3close inlet ,conduits 9 and Ill respectively. Valve stems I4 and of thevalves are situated on the casing side of the valves.

A rigid partition I6 divides the easing into two compartments which arejoined for gas flow by peripheral passages ll. On each side of rigidpartition I6 thereare positioned diaphragms l8 and I9 forming sealeddiaphragm chambers 20, 2|. The inlets adjacent the'valves carry checkvalves 22, 23. The inlets on the upstream side of the check valves areconnected by passages 24, with diaphragm chambers 2|, 20 respectively.The diaphragms carry pins 26, 21 each having a lateral projection 28 onits extreme end (see Figure 3). A valve stem operating pin 29 slidablycarried by a hanger 30 is present in tailed description thereof,reference being had to I the accompanying drawing which constitutes apart of this s ecification, and wherein:

each compartment of the casing 8. Each pin 29 is connected to acompression spring 3| in 'such a manner that a quick acting. switcheffect is accomplished by moving the pin past an intermediate or deadcenter position (see Figure 2). A rotatable cam 32 having cammingmembers 33 and I4 is connected by an arm 35 with a link 36 which in turnis connected to pin 29. Abutment members 31 limit movement of pins 29away from the valve stems.

Movement of diaphragm pin 21 from the position shown in Figures 1 and 3upward will result in spring 3| snapping pin 29 into contact with valvestem ii to open valve I2. The' position of the parts at this point areshown in dotted lines in Figures 2 and 3. Movement of diaphragm pin 21downwardly from the position shown in Figure 3 will cause spring 3| tosnap pin 29 out of contactwith valve stem I4.

With a full cylinder connected toinlet 9-and with 10 pounds gas pressurepresent at that inlet, the 10 pounds pressure will be applied throughpassage 24 to diaphragm l9 and the pressure in casing; beingatmospheric, the diaphragm l9 and its pin 21 will move upwardly to causepin 29 to open valve l2. When a cylinder is then connected to inlet 19which terminates at valve 13, the 10 pounds applied through passage 25to diaphragm l8, will not appreciably mov the same since the pressure incasing I is now approximately pounds minus the small pressure dropacross valve l2. When the gas flowing through the valve l2 begins todrop in pressure due to depletion of the liquefied gas in the associatedcylinder, the pressure in diaphragm chamber II will also begin to dropand the pressure in casing 8 will begin to drop. At the same time due tothe fact that the pressure in diaphragm chamber is being maintained at10 pounds, diaphragm l8 and its pin 26 will begin to move outwardlyuntil at a pressure of, for example, '7 pounds in casing O, valve Itwill open by the sequence of actions described above for valve ii. Thepressure in casing 8 will immediately rise to approximately 10 pounds,check valve 22 will close and diaphragm l9, due to the pressuredifferential present, will move downwardly operating cam member 32 aswill be obvious in Figure 3 to snap pin 29 off valve stem ll.-

It will be understood that the valve operating member made up ofelements 29, 3|, 3|, 3!, 33,

. conduits, an outlet conduit connected to the inlet conduits, a valvecontrolling-each inlet conduit and normally urged into closed position,a valve operating member for each valve movable between two positionsand opening the associated valve in one or the two positions, fluidpressure operated means associated with the valve operating members tochange the position of the same, the fluid pressure operated means beingsubjected to the pressure in the outlet conduit, and means for applyingan operating pressure to the fluid pressure operated means from a pointin each inlet conduit.

2. A changeover device comprising two inlet conduits, an outlet conduitconnected to the inlet conduits, a valve controlling each inlet conduitand normally urged into closed position, a valve operating member foreach valve movable between two positions and opening the associatedvalve in one of the two positions, fluid pressure operated meansassociated with each valve operating member, means for applying thepressure diflerential between the associated inlet conduits and theoutlet conduit to the fluid pressure oper- V ated means.

3. A changeover device comprising a body member having two fluid inletsand a fluid outlet, conduits connecting the inlets and the outlet, valvemeans including a valve controlling each conduit, valve operating meanshaving two positions associated with each valve and acting to open theassociated valve in one position, fluid pressure operated means operablein response to pressure differential across the valve means to move thevalve operating means from one position to the other.

4. A changeover device comprising two inlet conduits and an outletconduit, a valve controlling each inlet conduit normally in closedposition, a valve operating member for each valve, each valve operatingmember movable from one extreme position to another and acting to openits associated valve in one position, fluid pressure operated meansassociated with each valve and acting in response to pressuredifferential between a point on one side of the valve and theoutletconduit, connecting means acting between the valve operatingmembers and the fluid pressure operated means to move a valve operatingmember from one extreme position to another on the presence'of apredetermined pressure ditferential on the fluid pressure operatedmeans.

JAMES J. SHANLEY.

